Nail Yakupov quite likely is the worst player chosen by the Oilers in recent memory. Inspite the fact that he went first overall in the 2012 entry draft he was -4 in his first season with the team. This means that his overall contribution was negative after scoring 17 goals and adding 14 assists in 48 games (less than a point a game).
Now you may argue that +/- does not truly reflect the worth and contribution of a player, after all he is playing with others on his line who may contribute to his demise. That is true, however, when you go -33 in your next season and are a positive contributor in only 7 of the 63 games that you played, a pattern emerges.
+/- may not be a true indication of how Yak played last season, but if you look at his game log for the 2013-14 NHL season, you may notice that he was on the ice for only 7 games where his net contribution was positive. There were only 7 games where Yak’s +/- equaled to his points in that game. In contrast he has 3 games where he was -4 (this is not your line-mates causing your demise, this is you not taking care of your own end) he also had 6 other games where he was -2 or worse.
This is not what you would expect prima facie from your number one pick. The Oilers could have traded their first selection, chosen Thomas Hertl and picked up some assets in the deal making the club better. Instead they will be sending Yakupov to the minors or to another team by the end of the year when Darryl Katz writes another letter to fans, apologizing for a second lost season, before Christmas.